Peel and core the apples, then cut into thin slices. Combine with raisins, walnuts, sugar, and cinnamon.
Roll out the dough very thinly. Grease the entire surface with vegetable oil, leaving approximately 2 cm around the edges ungreased.
Sprinkle 2 tablespoons of bread crumbs over half of the dough. Place the apple filling on this half, then sprinkle the remaining 2 tablespoons of bread crumbs on top.
Using a silicone mat, parchment paper, or kitchen towel underneath to prevent tearing, tightly roll the dough into a log and pinch the edges firmly to seal.
Beat the egg. Brush the beaten egg over the top of the strudel. Bake at 180°C (350°F) for 30 to 35 minutes until golden brown.